Agitator mounting for drum filters

ABSTRACT

An improved agitator mounting for drum filters having agitator pins located below the drum&#39;&#39;s center axis has been developed. The improved agitator mounting provides means for driving a submerged, suspended rake-type agitator through a pin and bearing means mounted through the wall of the filter tank. The improved mounting means, which may be completely removed from outside the tank, comprises bearing means mounted externally, a pin seating in said bearing means, said pin secured to the agitator arm by bolts or other means fastened externally, and a drive arm attached to said pin by external means. A boot may also be attached between the agitator arm and the tank wall to house the agitator mounting and provide a liquid seal to prevent liquid contact with the agitator mounting.

[451 Apr. 10, 1973 United States Patent [191 Davis et a].

m 5% mm Tm W mm Lm mm y Sm m We To y NW my w AGITATOR MOUNTING FOR DRUMFILTERS [75] Inventors: Steven S. Davis, Bountiful; Morris F.

Durrant, Centerville, both of Utah Primary Examiner-Robert W. Jenkins Al73 Assignee: Envirotech Corporation, Salt Lake Ass'smmExamm cantoAttorney-Robert R. Finch, Richard F. Bojanowski and William S. BrittCity, Utah 221 Filed: Mar. 4, 1971 21 Appl.No.: 120,804

[57] ABSTRACT An improved agitator mounting for drum filters havingagitator pins located below the drums center axis has [52] US. Cl...................259/l01, 210/383, 210/402,

been developed. The improved agitator mounting pro- 259/DlG- 16, 2 Rvides means for driving a submerged, suspended rake- Bolf Bold 0 typeagitator through a pin and bearing means [51] Int.

[58] Field of Search......................2l0/327, 331, 402, mountedthrough the wall of the filter tank. The im- DIG. 16; proved mountingmeans, which may be completely 287/5206, 53;70/l88, 189,218 removed fromoutside the tank, comprises bearing means mounted externally, a pinseating in said bearing means, said pin secured to the agitator arm by[56] References Cited bolts or other means fastened externally, and adrive arm attached to said pin by external means. A boot may also beattached between the agitator arm and UNITED STATES PATENTS the tankwall to house the agitator mounting and provide a liquid seal to preventliquid contact with the agitator mounting.

14 Claims, 6 Drawing Figures xw 13 o 2 mm 1 ll, \u el l xefinaway$ m l/W|.\ W we 21 36 99 NH 96 PATENTE APR 1 0 ma SHEET 2 nr 2 w N E V mSteven 8. Da

ws BY Morris F Durranf FIGS Their Attorney AGITA'IOR MOUNTING FOR DRUMFILTERS BACKGROUND OF THE INVENTION Rake-type agitators have typicallybeen driven in two ways: (1) Above the trunnion mounting with areciprocating drive rod; and (2) Below the trunnion mounting with a pindrive through the filter wall. The

former system requires a larger tank since the agitator swings on aradius greater than the drum radius. Also, the former system isdifficult to use with fully enclosed filters inasmuch as it is difficultto provide a seal about a reciprocating rod passing through theenclosure.

Swinging the agitator through a bin mounted in the tank wall hasgenerally presented corrosion problems because the pin and associatedbearing are located below the liquid level of the filter tank.Furthermore, assembly or disassembly of a pin-driven agitator wastedious because of limited internal working space in which to connect ordisconnect the agitator arm from the pin.

DESCRIPTION OF THE INVENTION An improved agitator mounting and pin-driveassembly for driving drum filter agitators has been developed. Theimproved system comprises bearing means which mounts externally on theexterior wall of a filter tank and communicates with an opening in saidtank wall, and pin means passing through said bearing means, said pinmeans engaging an agitator arm on one end and engaging a crank at theother end. Fastening means are provided which pass through the pin meansto engage an agitator arm. Disengaging means are also provided whichpermits complete external disassembly of said improved agitatormounting. A boot-type seal may encompass the bearing means and pin meansto seal the bearing surfaces from contact with liquid.

The agitator drive mounting assembly of this invention is advantageousinasmuch as the agitator pivot point is located below the filter drumtrunnion thereby permitting use of a smaller filter tank and the wholefilter may be enclosed. Furthermore, the pin drive bearing surfaces maybe sealed and the whole agitator drive mechanism may be externallyassembled or disassembled.

Further understanding of the invention may be facilitated by referenceto the attached drawings.

FIG. 1 is a perspective view of a rotary drum filter having an agitatorpin-drive mounted below the filter drum trunnion.

FIG. 2 is an expanded perspective view of the agitator drive mountingassembly of FIG. 1.

FIG. 3 is a cross-sectional, elevational view of a multicomponentagitator drive mounting having bolt-type disassembly means.

FIG. 4 is a cross-sectional, elevational view of a mu]- ticomponentagitator drive mounting assembly having a pin-type disassembly means.

FIG. 5 is a perspective view of a flexible boot-type seal for sealingpin-type agitator mounting assemblies.

FIG. 6 is a cross-sectional, elevational view of a boottype seal insealing placement about a pin-type agitator or mounting assembly.

In FIG. 1 there is illustrated a drum filter of conventional type havinga cylindrical drum 10 supported by trunnions 11 and immersed in asemi-cylindrical tank 12 holding a slurry or other liquid-solids mediato be filtered. A rake-type agitator of curved cross-section andextending substantially the length of the tank is driven in anoscillating or reciprocating fashion by a pin 14 extending through anend wall of said tank below the filter trunnion. The pin 14 is rotatedthrough an arc of less than 10 depending upon the length of the raketypefilter by a crank 15 and drive arm 16 attached eccentrically to a rotarydrive mechanism 17 driven by a motor 18.

The rake-type agitator 13 is supported by agitator arms 19 which dependfrom the pin 14. The rake-type agitator maintains solids in suspensionby its pendulumlike motion. Because the drum filter occupies most of thetank volume, there is little space on the interior of the tank forworking. Suspending the agitator arms at a point below the filtertrunnion permits the agitator to circumscribe an arc of less radius thanthe radius of the filter drum thereby eliminating the need for a largerholding tank, such as is required when the agitator arms are suspendedat a point above the trunnion.

The agitator drive assembly of FIG. 1 is illustrated in FIG. 2 inexpanded fashion to facilitate understanding of the relationship andfunction of the components of the assembly. Bearing means 20 is shownmounted externally to the tank wall 21, said bearing means having acylindrical sleeve bearing 22 to receive a pin 14 which engages agitatorsupport 24 and crank 15 so as to transmit motion from the crank to theagitator support 24. The pin has a protrusion on each end to engage arecessed area in the agitator support 24 and the crank to providepositive drive means without placing any stress on the fastening meanswhich holds the assembly together. Alternatively, the pin can be slottedwith tongues protruding from the agitator support and crank.

' The protuberance or tongue 26 engages a slot or recess 27 in the faceof the agitator support 24. The tongue 26 may be tapered slightly sothat it is smaller at its extremity than it is at the base to facilitatemating of the tongue 26 with the recess 27 which may have similarlytapered surfaces. The mating surface 28 of the agitator arm which mateswith the tongue 26 of the pin 14 is angled slightly away from the pin 14to accommodate ease of insertion of the tongue 26. I

The pin 14 is joined with the agitator support by bolts 29 and 30 whichthread into the recess 27 on the agitator support. The crank 15 issecured to the pin 14 by bolts 31 and 32 which thread into the pin 14.Bolt 33 is a jack screw which is tightened during assembly only withsufficient force to cause it merely to contact the base of recess 27 ofthe agitator support. Jack screw 34 threads through the crank 15 andbutts against the head of bolt 33. Since pin 14 effects a tongue andgroove fit with crank 15 by means of the protrusion 35 fitting into theslot or keyway 36 it is possible for the pin 14 and crank 15 to becomewedged together even when screws 31 and 32 are removed. The crank 15 isreadily separated from pin 14 by tightening of jack screw 34 whichforces the crank 15 away from the pin 14. In a similar fashion, thetightening of jack screw 33 separates the pin 14 and agitator support 24once the retaining bolts 29 and 30 are removed. The whole assembly maybe disassembled externally inasmuch as the bearing assembly 20 issecured to the exterior of the tank by stud bolts 37 and 38 and anotherpair of stud bolts not illustrated.

FIG. 3 illustrates in cross-section another arrangement for securing thecrank to the agitator support 24 in a manner to enable the wholemechanism to be disassembled externally. A single holding bolt 41extends through the crank 15 and the pin 42 into a threaded hole in theagitator support 24. In assembling the mechanism, the pin 42 is matedwith the agitator support 24 so that the protrusion 43 of the pin fitsinto the slot 27 of the agitator support. The crank is then mated to thepin 42 in a similar fashion and the-single retaining bolt 41 fastenedinto the agitator support 24 to hold the assembly together. Fordisassembly, the single bolt 41 is removed and jack screw 45 is threadedthrough the pin 42 to butt against agitator support 24. Furthertightening of the jack screw 45 separates the pin 42 from the agitatorsupport 24. Jack screw 45 is 1 not threaded into crank 15 but ispreferably removed prior to tightening of jack screw 46 which is used toseparate the crank 15 and pin 42. The pin 42 of FIG. 3 differs from pin15 of FIG. 2 in the number of bolt holes passing therethrough.

In FIG. 4 a slightly different arrangement than illustrated in FIG. 3 ispresented. The assembly, shown-in cross-section, comprises a crank 15, aconnecting pin 48, an agitator support 24 and a single, centrallylocated bolt 50 which threads into the crank 15 and the agitator support24 to hold together the whole assembly. The mechanism is disassembled byremoving bolt 50 and tightening jack screw 51 which, through rod 52,puts pressure on the agitator support. During this operation the crank15 and pin 48 are held together by bolt. 53. The crank 15 and pin 48 areseparated by removing bolt 53 and further tightening jack screw 51 whichis threaded into the crank until the jack screw places pressure on thebutt surface 54 of the pin to separate the crank and pin. The diameterof jack screw 51 is greater than that of rod 52 or the passagewaycontaining rod 52. The pin 48 differs from the pins illustrated in FIG.2 and 3 in the number and arrangement of bolt holes present.

A boot for sealing the bearing surfaces of the agitator drive assemblyfrom liquid is illustrated in FIGS. 5 and 6. The boot 80 is cylindricalin shape with a lip 55 attached to cylinder 56 which has a base 57 witha slotlike hole 58 which accommodates the tongue or protrusion of ashaft for mating with a slot of an agitator arm. The boot is preferablyof rubber or similar flexible material which will accept a twistingaction of about less than ten degrees. The cooperation of the boot ofFIG. 5 with a typical pin-drive assembly of this invention isillustrated in FIG. 6 wherein the boot 80 is illustrated incross-section. The boot lip 55 is external to a tank wall 21 and placedbetween the flange portion of bearing means and the tank wall 21 so thatwhen the flange is tightened against the tank wall 21 a sealing effectwill be accomplished. A pin 14 having a protrusion or tongue 26projecting through the slot 58 of the boot 80 mates with a keyway orslot 27 of the agitator support 24. Upon tightening of the bolts whichsecure the pin 14 to the agitatorsupport 24 a seal is effected about theboot 80 so that no liquid can seap into the bearing surfaces existingbetween pin 14 and cylindrical sleeve 22. A boot of this type ispreferred in the instant invention inasmuch as the whole assembly may bedisassembled externally and the boot itself may be removed from aposition outside of the tank.

Other types of boots may be utilized, for example, a sleeve-type bootmay be utilized wherein one end of an open cylindrical sleeve may beslipped over the cylindrical portion of the agitator arm protrusion andtightened thereto with a ring-clamp. The other open portion of thesleeve may be slipped over the cylindrical protrusion of the bearing andsecured thereto with a ring-clamp.

Although the instant invention has been described hereinabove withreference to specific embodiments, it is to be understood that theinvention is not to be limited solely thereto but to include all thevariations and modifications falling within the scope of the appendedclaims.

We claim:

1 An agitator drive assembly for mounting below the trunnions ofdrum-type filters at least partially enclosed by a filter tank, saidassembly comprising:

a. bearing means mounted against an exterior wall of said filter tankand communicating with an opening in said tank wall,

. removable pin means passing through said bearing means, said pin meansadapted to engage an agitator support,

. removable fastening means extending through said pin means securingsaid pin means to said agitator support,

means for externally driving said pin means, and

external means for disengaging said pin means from said agitatorsupport.

2. The agitator drive assembly of claim 1 wherein said bearing means hasa cylindrical interior bearing surface.

3. The agitator drive assembly of claim 1 wherein said pin means engagesthe agitator support in driving fashion.

4. The agitator drive assembly of claim 1 wherein said fastening meanscomprises at least one bolt passing through said pin means to engage'athreaded opening in said agitator support.

5. The agitator drive assembly of claim 1 wherein said means for drivingsaid pin means comprises a crank arm, the free end of said crank armbeing reciprocally driven to describe an arc in its travel.

6. The agitator drive assembly of claim 5 wherein said crank arm issecured to said pin means by removable fastening means.

7. The agitator drive assembly of claim 6 wherein 'extemal disengagingmeans is adapted to disengage said crank arm from said pin means.

8. The agitator drive assembly of claim 6 wherein said fastening meanscomprises at least one bolt passing through said crank arm and said pinmeans to engage a threaded opening in said agitator support.

9. The agitator drive assembly of claim 6 wherein said fastening meansincludes a second bolt which secures said crank arm only to said pinmeans and a single disengaging means for disengaging said pin means fromsaid agitator support and for disengaging said crank arm from said pinmeans.

10. The agitator drive assembly of claim 9 wherein said singledisengaging means comprises at least one jack screw engaging threadsonly in said crank arm and engaging a rod which passes through a borehole in said pin means and is slightly longer than said pin means andwherein said jack screw has a greater diameter than the bore hole ofsaid pin means.

port and encompasses at least a portion of the bearing member protrudinginto said tank to prevent liquid from contacting the bearing surfacesof'said pin and bearing.

14. The agitator drive assembly of claim 13 wherein the flexibleboot-like seal possesses a lip at its open end which is adapted tocontact the exterior wall of said tank in a sealing fashion.

1. An agitator drive assembly for mounting below the trunnions ofdrum-type filters at least partially enclosed by a filter tank, saidassembly comprising: a. bearing means mounted against an exterior wallof said filter tank and communicating with an opening in said tank wall,b. removable pin means passing through said bearing means, said pinmeans adapted to engage an agitator support, c. removable fasteningmeans extending through said pin means securing said pin means to saidagitator support, d. means for externally driving said pin means, and e.external means for disengaging said pin means from said agitatorsupport.
 2. The agitator drive assembly of claim 1 wherein said bearingmeans has a cylindrical interior bearing surface.
 3. The agitator driveassembly of claim 1 wherein said pin means engages the agitator supportin driving fashion.
 4. The agitator drive assembly of claim 1 whereinsaid fastening means comprises at least one bolt passing through saidpin means to engage a threaded opening in said agitator support.
 5. Theagitator drive assembly of claim 1 wherein said means for driving saidpin means comprises a crank arm, the free end of said crank arm beingreciprocally driven to describe an arc in its travel.
 6. The agitatordrive assembly of claim 5 wherein said crank arm is secured to said pinmeans by removable fastening means.
 7. The agitator drive assembly ofclaim 6 wherein external disengaging means is adapted to disengage saidcrank arm from said pin means.
 8. The agitator drive assembly of claim 6wherein said fastening means comprises at least one bolt passing throughsaid crank arm and said pin means to engage a threaded opening in saidagitator support.
 9. The agitator drive assembly of claim 6 wherein saidfastening means includes a second bolt which secures said crank arm onlyto said pin means and a single disengaging means for disengaging saidpin means from said agitator support and for disengaging said crank armfrom said pin means.
 10. The agitator drive assembly of claim 9 whereinsaid single disengaging means comprises at least one jack screw engagingthreads only in said crank arm and engaging a rod which passes through abore hole in said pin means and is slightly longer than said pin meansand wherein said jack screw has a greater diameter than the bore hole ofsaid pin means.
 11. The agitator drive assembly of claim 1 wherein saidmeans for disengaging said pin means comprises at least one jack screwfor engaging threads in said pin means and passing through said pinmeans to butt against said agitator support.
 12. The agitator driveassembly of claim 1 wherein said bearing means protrudes through saidopening in said tank wall.
 13. The agitator drive assembly of claim 1wherein a flexible boot-like seal is attached to the agitator supportand encompasses at least a portion of the bearing member protruding intosaid tank to prevent liquid from contacting the bearing surfaces of saidpin and bearing.
 14. The agitator drive assembly of claim 13 wherein theflexible boot-like seal possesses a lip at its open end which is adaptedto contact the exterior wall of said tank in a sealing fashion.